1. Technical Field of the Invention
The present invention relates to a method for producing fuel injection control systems which control injection of fuel in internal combustion engines.
2. Related Art
A fuel injection control systems is known which is provided with a common rail serving as a common accumulator for supplying high-pressure fuel into fuel injection valves of respective cylinders of a diesel engine. In this common-rail type of fuel injection control for diesel engines, injection periods (during each of which the injection lasts), which are necessary for operating fuel injection valves, are set depending on an amount of fuel to be demanded and fuel pressure in the common rail.
There is variability (irregularity) in injection characteristics, which are due to the individual specificities of respective fuel injection valves. For producing the fuel injection valves, it is general that the variability is allowed. Thus, even when the injection periods are adjusted to depend on the fuel pressure so that the fuel is injected under the foregoing demanded fuel amounts, the amounts of the fuel to be injected for actual use varies due to the variability in the above injection characteristics.
One countermeasure to improve this situation has been proposed in Japanese Patent Laid-open Publication No. 2000-220508, which teaches the manufacturing process for fuel injection valves. In this manufacturing process, each fuel injection valve is subjected to measurement of its fuel injection characteristics, and based on the resultant characteristics, a correcting amount to correct a difference between a demanded fuel amount and the actual injection amount is computed for the correction. Further, a fuel injection valve which corresponds to the correcting amount is amounted in a diesel engine with a fuel injection control system, data indicative of the computed correcting amount is made to be stored in a fuel injection control apparatus which plays a control part in the system.
However, when the foregoing technique involving the correcting amount is used, the fuel characteristics of each fuel injection valve should be measured for every operation range to which a demanded correcting amount belongs. This causes an adjustment process for the fuel injection control to be complicated considerably, whereby this is not negligible.
In addition, the above drawback is not limited to the fuel injection control system for the diesel engine. That is, even in the case of a fuel injection control system controlling the injection of fuel in the internal combustion engine, the adjustment process for the fuel injection control is made complicated in greater or lesser degrees. Hence this negligible drawback is also true of the fuel injection control system for the internal combustion engine.